Objective-C XML parser

XmlParser.h

#import <Foundation/Foundation.h>

@interface XmlParser : NSObject <NSXMLParserDelegate>

@property (strong, nonatomic) NSData *xmlData;
@property (strong, nonatomic) NSMutableDictionary *dictionary;
@property (strong, nonatomic) NSMutableDictionary *currentNode;
@property (strong, nonatomic) NSMutableDictionary *currentParentNode;

- (id)initWithXMLData:(NSData *)xmlData;

- (NSMutableDictionary *)dictionary;

@end

XmlParser.m

#import "XmlParser.h"

@implementation XmlParser

@synthesize xmlData = _xmlData, dictionary = _dictionary, currentNode = _currentNode, currentParentNode = _currentParentNode;

- (id)initWithXMLData:(NSData *)xmlData
{
    if(self = [super init]){
        _xmlData = xmlData;
    }
    return self;
}

- (NSMutableDictionary *)dictionary
{
    if(!_dictionary){
        _dictionary = [[NSMutableDictionary alloc] init];
        
        NSXMLParser *parser = [[NSXMLParser alloc] initWithData:self.xmlData];
        parser.delegate = self;
        [parser parse];
        
    }
    return _dictionary;
}

- (NSMutableDictionary *)currentNode
{
    if(!_currentNode){
        _currentNode = _dictionary;
    }
    return _currentNode;
}

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
    NSMutableDictionary *node = [[NSMutableDictionary alloc] init];

    [self.currentNode setObject:node forKey:elementName];
    self.currentParentNode = self.currentNode;
    self.currentNode = node;
    
    if([attributeDict count] != 0)
    {
        [self.currentNode setObject:attributeDict forKey:@"attributes"];
    }
}

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
{
    self.currentNode = self.currentParentNode;
}

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
    NSString *trimmedString = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
    
    if([trimmedString length] != 0){
        [self.currentNode setObject:trimmedString forKey:@"value"];
    }
}

@end

...and then there's the problem with this fragment:

<parent><child>A</child><child>B</child></parent>

Subnodes with the same name collide in the dictionary, and the last subnode is the only one represented in the final structure. This is what we get for the above fragment:

parent {
    child {
        value {
            B
        }
    }
}